<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>内边距</title>
    <style type="text/css">
        #box1 {
            width: 100px;
            height: 100px;
            padding: 20px;
            border: 1px solid red;
            font-size: 20px;
        }
    </style>
</head>

<body>
<!--TODO 加强对盒子模型的理解-->
<div id="box1">盒子盒子盒子盒子盒子盒子盒子盒子盒子盒子</div>
</body>

</html>